This document relates to interference reduction in communication signals.
Given any particular signal power relative to noise, it is possible to achieve the highest channel capacity by spreading a signal across as much spectrum as possible. Thus, optimal utilization of spectrum may be achieved by spreading a signal across as much spectrum as possible. Optimal channel capacity can be achieved by making a signal as much like Additive White Gaussian Noise as possible. Furthermore, low error rates can be achieved by using Forward Error Correction.
This aspect of spectrum utilization also provides for uncoordinated band allocation in which a signal in the band appears as noise in relation to other signals in the band. Such uncoordinated band allocation results in optimal cumulative spectrum utilization. Utilization can be increased using Multiple-Input, Multiple-Output (MIMO), which uses multiple antennas at both the transmitter and receiver to improve communication performance. MIMO increases spectrum capacity in accordance with the number of transmit antennas and receive antennas above what could otherwise have been achieved because the number of independent channels available in a given spectrum band is increased.
Whether in a MIMO system or other communication system, a wireless device may often receive communications from two or more base stations, e.g., cellular towers. Receiving such multiple communications can cause interference and degrade signal quality.